Joanna P. Williams
Teachers College, Columbia University
The 1975 Education for All Handicapped Children Act ( Public Law 94-142) and the 1991 Individuals with Disabilities Education Act (IDEA) and its 1997 Amendments reflect our nation's strong commitment to bringing all individuals to full participation in all aspects of life. Research in special education has grown tremendously as a result of this legislation and commitment. In fact, the number of research studies has increased so voluminously that it has become difficult to sift through all the findings to determine what in fact the current state of our knowledge really is.
Meta-analysis provides a methodology for synthesizing a set of research findings so that we can identify those that hold up across studies and determine to what extent a finding can be generalized across populations and across settings. Such syntheses also reveal gaps in our knowledge and suggest questions for further empirical investigation.
In addition, meta-analysis also helps make findings visible and accessible, so that they become easier to interpret and to consider in policy formulation. In education, where public policy is determined in large part by social needs, values, and political concerns, it is especially important to have a clear understanding of what the research evidence shows, so that it will be given the weight it deserves in making policy.
One of the main themes of research in special education--perhaps its main theme--is intervention. How can we design and develop instructional interventions that will yield the most effective outcomes? The "special" in